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Assessing dental patients for their risk of being carriers of a blood-borne virus: the views of final year dental students
J. Dent. 1993;21:
99-104
99
Assessing dental patients for their risk of being carriers of a blood-borne virus: the views of final year dental students* N. M. Nuttallt
and A. D. Gilbert*
tDental Health Services Research Unit, Department of Dental Health and $Department Periodontology, University of Dundee, Park Place, Dundee, Scotland, UK
of Dental Surgery and
ABSTRACT Aquestionnaire was sent to final year dental students in all but one ofthe dental schools in the UK in 1991.The response was 447 out of 739 (60.5%). The students were asked about how they intended to approach various aspects of patient care once they were qualified and in practice. Almost half (44%) said they would use a crossinfection policy in which precautions would be stepped up for ‘risky’ patients. This study was undertaken to determine what they think are factors which might identify a patient who is infected, or at risk of being infected. by either hepatitis B virus or the human immunodeficiency virus. Those who said they would take personal histories to determine a patient’s risk (30%) seemed prepared to ask about experiences which have relatively low predictive value for infection (e.g. blood transfusions), yet are reluctant to ask more pertinent questions, i.e. those concerning sexual activity. Those who would attempt to assess patients’ risk status without asking ‘intrusive questions’ (14%) seem to have differing views about what sort of observable factors would be useful in framing such an assessment. KEY WORDS: J. Dent. 1993;
Cross-infection; 21:
99-l
Dental practice; Hepatitis
04 (Received
3 September
B virus; Human immunodeficiency
1992;
accepted
Correspondence should be addressed to: Dr N. Nuttall, DHSRU, Dundee, Park Place, Dundee DDI 4HR. Scotland, UK.
INTRODUCTION Vast improvements have been made in the level of uptake of specific types of cross-infection precautions, such as the use of surgical gloves in routine patient care, among general dental practitioners over the last few years (Pitts and Nuttall. 1988: Scullyetal., 1992). Nevertheless, despite recommendations that a universal cross-infection policy is the most appropriate approach to the management of routine dental patients (Centers for Disease Control, 1989; British Dental Association, 1991), many dentists undertake some form of risk assessment of their patients (Gerbert, 1987; Kay et al., 1990) and do so in order to step up precautions when treating those perceived to be at risk of being a blood-borne virus carrier (Lindsay and New, 1992). Similar behaviour has also been reported among final year dental students (see pp. 105-I 10, Nuttall and Gilbert, 1993). Kay et al.. (1990) have pointed out that *British
Conference.
Psychological Society Health St Andrews. September 1992.
0 1993 Butterworth-Heinemann 0300-57 11/93/020099-06
Ltd.
Psychology
Section
16 September
Department
virus
1992)
of Dental Health, University of
taking a patient’s history will not completely safeguard a dentist against unknowingly treating a human immunodeficiency virus (HIV)-positive patient, and Lindsay and New (1992) have gone so far as to argue that ‘even at its most reliable such case identification would have almost no chance of increasing dentists’ chances of identifying HIV-infected patients’. There are also some specific types of routine precautions, such as surgical masks and eye protection, which have been recommended but which many dental practitioners are still not prepared to use on a routine basis (Pitts and Nuttall. 1988: Scully et al., 1992). This might reflect a lack of belief in the efficacy of some precautions. however. the fact that many dentists say they would use some of them when they were treating a known HIV carrier. but not routinely (Pitts and Nuttall. 1988). suggests the reasons for non-compliance to certain guidelines in routine practice may be rather more complex. The purpose of this study was to examine the methods by which final year dental students would attempt to
100
J. Dent. 1993;
21: No. 2
identify a patient who may be a greater than average risk of being infected by either hepatitis B virus (HBV) or the human immunodeficiency virus.
MATERIALS
AND METHODS
The deans of all 16 dental schools in the UK were contacted and asked for their permission to send a questionnaire to each of their final year dental students. An undertaking was made to keep the results relating to any individual student or individual dental school confidential. All except one dental school agreed to take part. A contact individual was identified in each school who was asked to supply a list of the names of the final year students and later to arrange for the questionnaires to be distributed. The students returned their completed questionnaire directly by post. The students were asked to ‘try to use the questionnaire to think through how you intend to approach the dental management of carriers, or potential carriers, of blood borne viruses’. A number was stamped on each individual questionnaire to allow nonrespondents to be identified and re-contacted with a second questionnaire and reminder note. The final return was 447 out of 739, a response rate of 60.5%.
RESULTS The students were asked to evaluate the undergraduate teaching they had received about recognition of bloodborne virus risk groups. Most (65%) said they felt it was adequate and a further 17% thought that it was more than adequate (Fig. 1). They were also given a list of 30 patient categories and asked whether they would regard these patients as a higher, lower or average risk of being HIV positive. or of being HBV positive. In Table I the factors have been ordered into perceived risk groups on the basis of the percentage of the students who assigned them to each particular risk group for HIV or for HBV. The factors None (1%) Less
than
More
adequate
than
adequate
have been listed in Table I in order of the perceived degree of risk each factor presents on the basis of the pooled views of the students. Only the percentage of students assigning a category as high or low is shown: the percentage who regarded a category as average risk can be determined by adding the high and the low score and subtracting from 100. Intravenous heroin users, male homosexuals and male bisexuals were regarded as a higher than average risk for HIV by over 90% of students. Immunosuppressed or immunodeficient patients, residents and staff of long-stay institutions and renal dialysis unit staff were regarded as high risk for HBV by more than half of the students, but less than half thought they would also be high risk for HIV. Down’s syndrome individuals were difficult to classify, most students felt they would be an average (41%) or high (44%) risk for HBV but said they would be an average (50%) or low (34%) risk for HIV. Over a third of the students said they thought that tourists from the former Soviet Union and Japan would be a lower than average risk for HIV. About a third of students said they also thought that blood donors would be a lower than average risk both for HIV and for HBV. Female homosexuality was considered the lowest risk of the factors examined. The students were also asked whether they intended to use the same cross-infection precautions for all patients or whether they would try to assess whether a patient was a member of a high-risk group in order to step up precautions. A total of 125 (30%) said they would question some (15%) or all (15%) of their patients to assess whether they were a member of a high-risk group so that additional cross-infection precautions could be taken (Fig. 2). These 125 students were asked to identify which questions. from a list of 11, they would consider relevant and would be prepared to ask their patients. Their responses are shown in Table II. Most (87%) said they would ask about intravenous drug use. however, few said they would be prepared to ask questions about whether a patient was sexually active (22%) and the number of sexual partners they were involved with (18%). Fig. 2 shows that 14% of the students said they would attempt to assess whether a patient was a member of a high-risk group without asking intrusive questions.
(17%)
(17%)
Assess questioning
risk
by
all patients ,at all patients
Assess
risk
by
questioning some patients (15%)
the same .......... ........... (55%) .......... ........... .......... ........... .......... ........... ........... ~.~.~.~.~.~.~.~.~.~.~.~ ............ ........... ............ ............ ............ ............ ........... .......... ~.~.~.~.~.~.~.~.~.~.~ .......... ........... ........... ........... ...........
. . ... ....
Assess Adequate
risk
withou
asking intrusive questions
[65%)
(14%)
1. Evaluation dental students. Fig.
of undergraduate
teaching
by final year
Risk assessment said they would use.
fig.
2.
strategies
that final year students
Nuttall
and Gilbert:
Assessment
of cross-infection
risk by students
101
Tab/e 1. Percentage of students (n = 447) who said that the following factors would put a patient into a high or low risk group for human immunodeficiency virus (HIV) and/or hepatitis B virus (HBV). For brevity the proportion who rated a factor as average risk are not included but they can be determined by taking 100 - (high + low). The factors have been ordered into perceived risk groups on the basis of the students’ responses HIV risk /%I High Low Perceived as high risk for HIV and HBV Intravenous heroin user Male homosexual Male bisexual Tourist from Nigeria Haemophiliac Tattooed patient
100 99 95 88 88 74
Perceived as high risk for HIV/average Tourist from Canada
to high for HBV
Perceived as high risk for HIV/average Long-stay institution resident Immunosuppressed/immunodeficient Staff of long-stay institutions Renal dialysis unit staff
to high for HIV patient
Perceived as average to high risk for HIV and HBV Female bisexual Down’s syndrome individual Patient who has recently received a whole blood transfusion in UK Tourist from South Africa Patient who has recently received blood products in UK Perceived as average risk for HIV and HBV Tourist from Netherlands Tourist from Boston Male heterosexual Female heterosexual Marihuana smoker Patient with granulomatous disease Diabetic patient Tourist from Denmark Perceived as average to low risk for HIV and HBV Tourist from Germany Tourist from Soviet Union Tourist from Japan Atherosclerotic patient Patient who is blood donor Female homosexual
Adding these to the group who said they would question some of their patients (15%) suggests that 119 (29%) of the students would attempt to use some form of outwardly observable signs or cues to identify potential high-risk patients. These students were asked to indicate what signs, from a list of nine factors, would make them think the patient could be a high risk of being a blood-borne virus carrier (Table III). None of the nine items were considered to be factors indicating high risk by the majority of students. The item on which greatest agreement was reached (46%) was the presence of visible tattoos. Table IV examines the reported level of use of six forms of precaution on a routine basis by students who said they would use the same cross-infection control policy for all patients and by students who said they would assess whether a patient was a member of a high-risk group in order to take additional cross-infection precautions where appropriate. Significantly fewer of those who said they
HBV risk (%) High Low
97 88 85 72 z
: :, 18 1
54
6
39
6
46 34 23 32
17 8 11 10
72 56 51 52
7 3 6 7
47 16
2 34
45 44
3 15
22
16
42
10
35 19
6 17
36 38
5 10
24 16 5 4 3 8
16 14 12 14 19 18 21 22
16 14 6 4 : 6 5
15 9 12 13 17 18 16 19
27 38 40 23 36 51
1 12 16 2 7 20
19 21 17 21 33 27
z
1 7 4 1 4 16
would assess risk said they would wear a gown (P < 0.05), eye protection (P < 0.01) or a surgical mask (P < 0.01) on a routine basis.
DISCUSSION The method The reliability of questionnaires as a means of determining actual clinical behaviour has been called into question (Scully et al., 1992). However. the method has been defended by the argument that a health professional’s working practice is likely to be based on considered judgement that it is in the best interest of the patient and that deliberately false responses to questionnaire items to conceal known shortcomings in clinical practice may therefore be a rare event (Nuttall and Gilbert, 1993). Nevertheless. in this particular study of final year dental
102
J. Dent. 1993;
21: No. 2
Table II. Topics that students who said they would attempt to assess the likelihood of a patient being a member of a highrisk group for carrying a blood-borne virus (H BV or HIV) by asking the patient specific questions would use in order to decide whether to take additional cross-infection precautions (n = 125, out of a sample of 447)
Table 111.Observable characteristics of patients cited by students who indicated that they would attempt to use such observable cues to assess the likelihood of a patient being a member of a high-risk group for carrying a blood-borne virus, HBV or HIV, in order to take additional cross-infection precautions (n = 1 19, out of a sample of 447)
Question
%
Observable characteristic
%
Whether they are an intravenous drug user? Whether they have recently had any tattoos? Their job? Sexual inclination Whether they have recently had a transfusion of whole blood? Whether they think they could be an undiagnosed carrier? Whether they have recently had a transfusion of blood products? Whether they know any one who is a carrier of a blood-borne virus? Whether they have recently donated blood? Whether they are sexually active? The number of sexual partners they have had in the recent past?
87 66 62 60
Visible tattoos ‘Unconventional’ male Visible spots
46 42 33 31 28 23 21 20 0
58 56 55 50 31 22 18
Table IV. Routine precautions claimed to be used by students who say they would use the same cross-infection control policy for all (no risk assessment), and by students who say they would assess a patient’s risk status in order to decide whether to step up precautions (risk assessors)
Routine precaution Disposable surgical gloves Re-usable surgical gloves Either disposable or re-usable gloves Surgical gown Eye protection Surgical mask Autoclave for hand instruments
No risk assessment f%)
Risk assessors (%I
61 32
54 39
NS NS
4
4
12 92 75
6 72 48
* ** **
98
99
NS
NS
Chi-squareusing Yates correction: NS, not significant, * P > 0.05, ** P > 0.01.
students it must be accepted that opinions about how to approach patient management might not be fully formed and might be modified by future clinical experience. However. the study ought to provide an insight into the effect of undergraduate training during a period when the impact of blood-borne viruses has been increasing.
Assessing
risk of infection
Just under half (44%) of the final year dental students who replied to the questionnaire said they would assess the likelihood that a patient might be a member of a high-risk group in order to take additional cross-infection precautions. Over two-thirds of these would do so by questioning their patients, and the remaining third said they would attempt to assess risk without resorting to asking intrusive questions. Similarly, Kay et al. (1990) have reported
Age Male with earrings ‘Unconventional’ female Where they live (i.e. neighbourhood) Gender Female with earrings
that two-thirds of a sample of Scottish general dental practitioners took medical, social and personal histories by means of verbal enquiry or a written history sheet in order to screen their patients for risk factors. The present study demonstrates one of the problems associated with taking personal histories. The vast majority of the final year dental students said they thought a male homosexual was likely to be a high-risk individual for HIV (99.8%) or HBV (87.8%). Yet, only 60% of those who would attempt to assess a patient’s risk said they would be prepared to ask patients about their sexual inclinination. However, they indicated that they would be far less reticent about asking patients about their use of intravenous drugs. Even fewer students said they would be prepared to ask their patients about other aspects of their sexual behaviour such as whether they were sexually active (22%) and the number of partners with whom the patient was involved (18%). These might be increasingly more relevant factors with the increasing incidence of HIV infection among the heterosexual population in many Western European countries (Pindborg, 1992). However, there is a view that replies about the number of sexual partners may not produce particularly good information about risk of contracting HIV infection as many sexual contacts may not involve et al., particularly risky sexual behaviour (Fitzpatrick 1989). This reluctance to question patients about their sexual activity is similar to that found among qualified general dental practitioners (Gerber?. 1987: Kay et al., 1990) and among general medical practitioners (Naji et al.. 1989) and may reflect either unease about asking such questions or concern about the quality of information they produce. Almost a third (31%) of students who said they would attempt to assess a patient’s risk status said they would ask whether the patient was a blood donor. Most students said they thought being a blood donor would indicate a person was an average to low risk of being infected by HIV (95.6%) or HBV (93.0%). This suggests they would use the information as a negative indicator of risk, rather than believing that donating blood is itself a risky behaviour. However, it ought to be matter for concern if such questions are being put to dental patients, as they may be
Nuttall
and Gilbert:
unaware of the subtlety underlying them and construe it as indicating that there is a risk associated with donating blood. The students also seemed to be concerned about the quality of blood transfusions in the UK; 22% said they would consider being a recent recipient of whole blood in the UK as an indication of high risk to HIV. Furthermore. over half (55%) of those who would question patients in order to establish their risk would ask if they had recently had a transfusion. Blood transfusions are a potential route for viral infection and accounted for 0.6% of cases reported to be HIV-antibody positive up to 1991 in Scotland; in comparison transmission by heterosexual intercourse accounted for 9.4% of cases (Common Services Agency, 1991). The students in this study therefore seem to be quite prepared to ask questions with relatively little predictive value but having the very real danger of causing considerable alarm and anxiety among some patients (those who have had blood transfusions). yet are not prepared to ask what are perhaps much more pertinent questions presumably because they might cause embarrassment. If dentists do intend to formulate their cross-infection strategies in conjunction with assessments of a patient’s risk (despite recommendations by authoritative bodies that they should not). they should be much more prepared to ask about behaviours which have a higher predictive value of risk. The students’ views on the relative risk of tourists from various countries can be compared with reported rates of AIDS infection throughout the world (Pindborg, 1992). German, Danish and Dutch tourists were regarded as average or lower risk for HIV infection by 99%. 91% and 76% of the students respectively: yet their reported rates of AIDS cases in 1990 (85. 127 and 94 cases per million) exceeds the reported rate of 60 cases per million in the UK. However. 38% of the students thought tourists from Japan would be a lower than average risk and the same view was held by 40% of the students about tourists from the former Soviet Union. These views would be borne out by their reported AIDS rates of 2.3 and 0.1 per million respectively. The 119 students who indicated that they would assess the risk status of patients using some sort of observable cues in order to step up their cross-infection precautions (14%) or in order to decide whether to ask questions which might reveal risk status (15%) were given a checklist of potential observable factors and asked which would make them think a patient may be a high risk. The finding that none of the items were identified as risk indicators by more than half of the students suggests that there may be a great deal of variability in opinion about which observable factors may aid identification of a high-risk individual. Classifying people as high or low risk by observation, without asking specific questions about behaviour. seems unlikely to be a particularly successful way of detecting a large proportion of undetected infected patients, although it is clear from this present study that some dental students think they are capable of doing so. as do some general dental practitioners (Kay et al., 1990).
Assessment
of cross-infection
risk by students
103
The significance of the finding that many final year dental students intend to base their future cross-infection strategies on assessments of their patients’ risk status depends on what is done with the information. It would be perhaps a rather different matter if, for example, an assessment of risk is undertaken to determine whether to wear two pairs of gloves rather than one, as against the information being used to decide whether to wear any gloves at all. The results suggest that almost all students, as a matter of routine, intend to wear some form of glove and use an autoclave for sterilizing hand instruments. However. there was less support for the routine use of surgical gowns, eye protection and surgical masks among the students who said they would assess the risk status of patients in order to step up cross-infection precautions when appropriate. This suggests that these might be the type of precautions which are used in addition to routine precautions by those who say they intend to use a twostage cross-infection strategy based on their perception of a patient’s risk.
CONCLUSION This study has found that final year dental students think they can identify high-risk patients by a variety of means. and would attempt to do so in order to step up their crossinfection control precautions. Those who would take personal histories seem prepared to ask about experiences which have relatively low predictive value for infection (e.g. blood transfusions). but some are reluctant to ask more pertinent questions, i.e. those concerning sexual activity. Those who would attempt to assess patients’ risk status by observation, without asking’intrusive questions’. seem to have differing views about what sort of factors would be useful in coming to an assessment. It is perhaps an evolutionary feature of human behaviour that people are natural assessors of risk and that actions will be tailored to fit an individual’s perception of the danger of any given situation. Nevertheless, there is perhaps a need when undertaking clinical work to override what may be a natural adaptive behaviour at other times. The danger in believing that the carrier status of patients can be reliably determined by questioning or observation. in order to decide when to take additional precautions. is that it may eventually lead to complacency in maintaining an adequate cross-infection control programme in routine clinical care.
Acknowledgements We would like to thank all the students who took the time to complete the questionnaire and the local contacts and Deans of the dental schools of Belfast. Birmingham, Bristol, Cardiff. Dundee. Edinburgh. Glasgow. Guys. Leeds. Liverpool, The London Hospital, Manchester, Newcastle, Sheffield, and University College, London. The study was supported by a grant from the Scottish
104
J. Dent. 1993;
21: No. 2
Office Home and Health Department who do necessarily share the views expressed in this article.
not
References British Dental Association (1991) The Control of Crossinfection in Dentistry. Advice Sheet A12. London. British Dental Association. Centers for Disease Control. (1989) Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis B virus to health-care and public-safety workers. MMWR 381 No. S-6. Common Services Agency (1991) Scotfish Health SraWics 1991. Edinburgh. Information and Statistics Division of the Commons Services Agency for the Scottish Health Service. p. 27. Fitzpatrick R.. Boulton M.. Hart G. et al. (1989) High risk sexual behaviour and condom use in a sample of homosexual and bisexual men. Health Trends 3, 76-79. Gerbert B. (1987) AIDS and infection control in dental practice: dentists’ attitudes. knowledge and behaviour. J. Am. Dent. Assoc. 114, 311-314.
Forthcoming Original
Research
Morphology
of coupling
Kay E. J., Murray K. and Blinkhorn A. S. (1990) AIDS and immunodeficiency virus: a preliminary investigation into Edinburgh general dental practitioners’ views and behaviours. Health Educ. Res. 5, 321-325. Lindsay S. J. E. and New M. (1992) Implementing universal precautions against infection. Br. Dent. J. 172, 297. Naji S.. Russell I., Moore M. et al. (1989) HIV Infection and Scottish General Practice. Findings of a National Sample Survey. Report No. 2. Aberdeen. Health Services Research Unit. Nuttall N. M. and Gilbert A. D. (1993) Final year dental students’ views on cross-infection precautions. J. Dent 105-l 10. Pindborg J. J. (1992) Global aspects of the AIDS epidemic. Oral Surs. Oral Med. Oral Pathol. 73, 138-141. Pitts N. B. and Nuttall N. M. (1988) Precautions reported to be used against cross-infection and attitudes to the dental treatment of HIV-positive patients in routine clinical practice in Scotland. J. Dent. 16, 258-263. Scully C.. Porter S. R. and Epstein J. (1992) Compliance with infection control procedures in a dental hospital clinic. Br. Dent. J. 173, 20-23.
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of resin-bonded
bridge
survivals,
comparing
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models
R. J. Smales, 7: L. Berekally and D. A. Webster
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systems
in cervical
and G. Vanherle
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with adult periodontitis
A. Rawlinson. B. I. Duet-den and L. Goodwin
Inhibition of serum albumin flux across exposed dentine following with GLUMA primer, glutaraldehyde or potassium oxalates G. Bergenholtz, M. Jontell, A. Tuttle and G. Knutsson
conditioning
99-104
99
Assessing dental patients for their risk of being carriers of a blood-borne virus: the views of final year dental students* N. M. Nuttallt
and A. D. Gilbert*
tDental Health Services Research Unit, Department of Dental Health and $Department Periodontology, University of Dundee, Park Place, Dundee, Scotland, UK
of Dental Surgery and
ABSTRACT Aquestionnaire was sent to final year dental students in all but one ofthe dental schools in the UK in 1991.The response was 447 out of 739 (60.5%). The students were asked about how they intended to approach various aspects of patient care once they were qualified and in practice. Almost half (44%) said they would use a crossinfection policy in which precautions would be stepped up for ‘risky’ patients. This study was undertaken to determine what they think are factors which might identify a patient who is infected, or at risk of being infected. by either hepatitis B virus or the human immunodeficiency virus. Those who said they would take personal histories to determine a patient’s risk (30%) seemed prepared to ask about experiences which have relatively low predictive value for infection (e.g. blood transfusions), yet are reluctant to ask more pertinent questions, i.e. those concerning sexual activity. Those who would attempt to assess patients’ risk status without asking ‘intrusive questions’ (14%) seem to have differing views about what sort of observable factors would be useful in framing such an assessment. KEY WORDS: J. Dent. 1993;
Cross-infection; 21:
99-l
Dental practice; Hepatitis
04 (Received
3 September
B virus; Human immunodeficiency
1992;
accepted
Correspondence should be addressed to: Dr N. Nuttall, DHSRU, Dundee, Park Place, Dundee DDI 4HR. Scotland, UK.
INTRODUCTION Vast improvements have been made in the level of uptake of specific types of cross-infection precautions, such as the use of surgical gloves in routine patient care, among general dental practitioners over the last few years (Pitts and Nuttall. 1988: Scullyetal., 1992). Nevertheless, despite recommendations that a universal cross-infection policy is the most appropriate approach to the management of routine dental patients (Centers for Disease Control, 1989; British Dental Association, 1991), many dentists undertake some form of risk assessment of their patients (Gerbert, 1987; Kay et al., 1990) and do so in order to step up precautions when treating those perceived to be at risk of being a blood-borne virus carrier (Lindsay and New, 1992). Similar behaviour has also been reported among final year dental students (see pp. 105-I 10, Nuttall and Gilbert, 1993). Kay et al.. (1990) have pointed out that *British
Conference.
Psychological Society Health St Andrews. September 1992.
0 1993 Butterworth-Heinemann 0300-57 11/93/020099-06
Ltd.
Psychology
Section
16 September
Department
virus
1992)
of Dental Health, University of
taking a patient’s history will not completely safeguard a dentist against unknowingly treating a human immunodeficiency virus (HIV)-positive patient, and Lindsay and New (1992) have gone so far as to argue that ‘even at its most reliable such case identification would have almost no chance of increasing dentists’ chances of identifying HIV-infected patients’. There are also some specific types of routine precautions, such as surgical masks and eye protection, which have been recommended but which many dental practitioners are still not prepared to use on a routine basis (Pitts and Nuttall. 1988: Scully et al., 1992). This might reflect a lack of belief in the efficacy of some precautions. however. the fact that many dentists say they would use some of them when they were treating a known HIV carrier. but not routinely (Pitts and Nuttall. 1988). suggests the reasons for non-compliance to certain guidelines in routine practice may be rather more complex. The purpose of this study was to examine the methods by which final year dental students would attempt to
100
J. Dent. 1993;
21: No. 2
identify a patient who may be a greater than average risk of being infected by either hepatitis B virus (HBV) or the human immunodeficiency virus.
MATERIALS
AND METHODS
The deans of all 16 dental schools in the UK were contacted and asked for their permission to send a questionnaire to each of their final year dental students. An undertaking was made to keep the results relating to any individual student or individual dental school confidential. All except one dental school agreed to take part. A contact individual was identified in each school who was asked to supply a list of the names of the final year students and later to arrange for the questionnaires to be distributed. The students returned their completed questionnaire directly by post. The students were asked to ‘try to use the questionnaire to think through how you intend to approach the dental management of carriers, or potential carriers, of blood borne viruses’. A number was stamped on each individual questionnaire to allow nonrespondents to be identified and re-contacted with a second questionnaire and reminder note. The final return was 447 out of 739, a response rate of 60.5%.
RESULTS The students were asked to evaluate the undergraduate teaching they had received about recognition of bloodborne virus risk groups. Most (65%) said they felt it was adequate and a further 17% thought that it was more than adequate (Fig. 1). They were also given a list of 30 patient categories and asked whether they would regard these patients as a higher, lower or average risk of being HIV positive. or of being HBV positive. In Table I the factors have been ordered into perceived risk groups on the basis of the percentage of the students who assigned them to each particular risk group for HIV or for HBV. The factors None (1%) Less
than
More
adequate
than
adequate
have been listed in Table I in order of the perceived degree of risk each factor presents on the basis of the pooled views of the students. Only the percentage of students assigning a category as high or low is shown: the percentage who regarded a category as average risk can be determined by adding the high and the low score and subtracting from 100. Intravenous heroin users, male homosexuals and male bisexuals were regarded as a higher than average risk for HIV by over 90% of students. Immunosuppressed or immunodeficient patients, residents and staff of long-stay institutions and renal dialysis unit staff were regarded as high risk for HBV by more than half of the students, but less than half thought they would also be high risk for HIV. Down’s syndrome individuals were difficult to classify, most students felt they would be an average (41%) or high (44%) risk for HBV but said they would be an average (50%) or low (34%) risk for HIV. Over a third of the students said they thought that tourists from the former Soviet Union and Japan would be a lower than average risk for HIV. About a third of students said they also thought that blood donors would be a lower than average risk both for HIV and for HBV. Female homosexuality was considered the lowest risk of the factors examined. The students were also asked whether they intended to use the same cross-infection precautions for all patients or whether they would try to assess whether a patient was a member of a high-risk group in order to step up precautions. A total of 125 (30%) said they would question some (15%) or all (15%) of their patients to assess whether they were a member of a high-risk group so that additional cross-infection precautions could be taken (Fig. 2). These 125 students were asked to identify which questions. from a list of 11, they would consider relevant and would be prepared to ask their patients. Their responses are shown in Table II. Most (87%) said they would ask about intravenous drug use. however, few said they would be prepared to ask questions about whether a patient was sexually active (22%) and the number of sexual partners they were involved with (18%). Fig. 2 shows that 14% of the students said they would attempt to assess whether a patient was a member of a high-risk group without asking intrusive questions.
(17%)
(17%)
Assess questioning
risk
by
all patients ,at all patients
Assess
risk
by
questioning some patients (15%)
the same .......... ........... (55%) .......... ........... .......... ........... .......... ........... ........... ~.~.~.~.~.~.~.~.~.~.~.~ ............ ........... ............ ............ ............ ............ ........... .......... ~.~.~.~.~.~.~.~.~.~.~ .......... ........... ........... ........... ...........
. . ... ....
Assess Adequate
risk
withou
asking intrusive questions
[65%)
(14%)
1. Evaluation dental students. Fig.
of undergraduate
teaching
by final year
Risk assessment said they would use.
fig.
2.
strategies
that final year students
Nuttall
and Gilbert:
Assessment
of cross-infection
risk by students
101
Tab/e 1. Percentage of students (n = 447) who said that the following factors would put a patient into a high or low risk group for human immunodeficiency virus (HIV) and/or hepatitis B virus (HBV). For brevity the proportion who rated a factor as average risk are not included but they can be determined by taking 100 - (high + low). The factors have been ordered into perceived risk groups on the basis of the students’ responses HIV risk /%I High Low Perceived as high risk for HIV and HBV Intravenous heroin user Male homosexual Male bisexual Tourist from Nigeria Haemophiliac Tattooed patient
100 99 95 88 88 74
Perceived as high risk for HIV/average Tourist from Canada
to high for HBV
Perceived as high risk for HIV/average Long-stay institution resident Immunosuppressed/immunodeficient Staff of long-stay institutions Renal dialysis unit staff
to high for HIV patient
Perceived as average to high risk for HIV and HBV Female bisexual Down’s syndrome individual Patient who has recently received a whole blood transfusion in UK Tourist from South Africa Patient who has recently received blood products in UK Perceived as average risk for HIV and HBV Tourist from Netherlands Tourist from Boston Male heterosexual Female heterosexual Marihuana smoker Patient with granulomatous disease Diabetic patient Tourist from Denmark Perceived as average to low risk for HIV and HBV Tourist from Germany Tourist from Soviet Union Tourist from Japan Atherosclerotic patient Patient who is blood donor Female homosexual
Adding these to the group who said they would question some of their patients (15%) suggests that 119 (29%) of the students would attempt to use some form of outwardly observable signs or cues to identify potential high-risk patients. These students were asked to indicate what signs, from a list of nine factors, would make them think the patient could be a high risk of being a blood-borne virus carrier (Table III). None of the nine items were considered to be factors indicating high risk by the majority of students. The item on which greatest agreement was reached (46%) was the presence of visible tattoos. Table IV examines the reported level of use of six forms of precaution on a routine basis by students who said they would use the same cross-infection control policy for all patients and by students who said they would assess whether a patient was a member of a high-risk group in order to take additional cross-infection precautions where appropriate. Significantly fewer of those who said they
HBV risk (%) High Low
97 88 85 72 z
: :, 18 1
54
6
39
6
46 34 23 32
17 8 11 10
72 56 51 52
7 3 6 7
47 16
2 34
45 44
3 15
22
16
42
10
35 19
6 17
36 38
5 10
24 16 5 4 3 8
16 14 12 14 19 18 21 22
16 14 6 4 : 6 5
15 9 12 13 17 18 16 19
27 38 40 23 36 51
1 12 16 2 7 20
19 21 17 21 33 27
z
1 7 4 1 4 16
would assess risk said they would wear a gown (P < 0.05), eye protection (P < 0.01) or a surgical mask (P < 0.01) on a routine basis.
DISCUSSION The method The reliability of questionnaires as a means of determining actual clinical behaviour has been called into question (Scully et al., 1992). However. the method has been defended by the argument that a health professional’s working practice is likely to be based on considered judgement that it is in the best interest of the patient and that deliberately false responses to questionnaire items to conceal known shortcomings in clinical practice may therefore be a rare event (Nuttall and Gilbert, 1993). Nevertheless. in this particular study of final year dental
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Table II. Topics that students who said they would attempt to assess the likelihood of a patient being a member of a highrisk group for carrying a blood-borne virus (H BV or HIV) by asking the patient specific questions would use in order to decide whether to take additional cross-infection precautions (n = 125, out of a sample of 447)
Table 111.Observable characteristics of patients cited by students who indicated that they would attempt to use such observable cues to assess the likelihood of a patient being a member of a high-risk group for carrying a blood-borne virus, HBV or HIV, in order to take additional cross-infection precautions (n = 1 19, out of a sample of 447)
Question
%
Observable characteristic
%
Whether they are an intravenous drug user? Whether they have recently had any tattoos? Their job? Sexual inclination Whether they have recently had a transfusion of whole blood? Whether they think they could be an undiagnosed carrier? Whether they have recently had a transfusion of blood products? Whether they know any one who is a carrier of a blood-borne virus? Whether they have recently donated blood? Whether they are sexually active? The number of sexual partners they have had in the recent past?
87 66 62 60
Visible tattoos ‘Unconventional’ male Visible spots
46 42 33 31 28 23 21 20 0
58 56 55 50 31 22 18
Table IV. Routine precautions claimed to be used by students who say they would use the same cross-infection control policy for all (no risk assessment), and by students who say they would assess a patient’s risk status in order to decide whether to step up precautions (risk assessors)
Routine precaution Disposable surgical gloves Re-usable surgical gloves Either disposable or re-usable gloves Surgical gown Eye protection Surgical mask Autoclave for hand instruments
No risk assessment f%)
Risk assessors (%I
61 32
54 39
NS NS
4
4
12 92 75
6 72 48
* ** **
98
99
NS
NS
Chi-squareusing Yates correction: NS, not significant, * P > 0.05, ** P > 0.01.
students it must be accepted that opinions about how to approach patient management might not be fully formed and might be modified by future clinical experience. However. the study ought to provide an insight into the effect of undergraduate training during a period when the impact of blood-borne viruses has been increasing.
Assessing
risk of infection
Just under half (44%) of the final year dental students who replied to the questionnaire said they would assess the likelihood that a patient might be a member of a high-risk group in order to take additional cross-infection precautions. Over two-thirds of these would do so by questioning their patients, and the remaining third said they would attempt to assess risk without resorting to asking intrusive questions. Similarly, Kay et al. (1990) have reported
Age Male with earrings ‘Unconventional’ female Where they live (i.e. neighbourhood) Gender Female with earrings
that two-thirds of a sample of Scottish general dental practitioners took medical, social and personal histories by means of verbal enquiry or a written history sheet in order to screen their patients for risk factors. The present study demonstrates one of the problems associated with taking personal histories. The vast majority of the final year dental students said they thought a male homosexual was likely to be a high-risk individual for HIV (99.8%) or HBV (87.8%). Yet, only 60% of those who would attempt to assess a patient’s risk said they would be prepared to ask patients about their sexual inclinination. However, they indicated that they would be far less reticent about asking patients about their use of intravenous drugs. Even fewer students said they would be prepared to ask their patients about other aspects of their sexual behaviour such as whether they were sexually active (22%) and the number of partners with whom the patient was involved (18%). These might be increasingly more relevant factors with the increasing incidence of HIV infection among the heterosexual population in many Western European countries (Pindborg, 1992). However, there is a view that replies about the number of sexual partners may not produce particularly good information about risk of contracting HIV infection as many sexual contacts may not involve et al., particularly risky sexual behaviour (Fitzpatrick 1989). This reluctance to question patients about their sexual activity is similar to that found among qualified general dental practitioners (Gerber?. 1987: Kay et al., 1990) and among general medical practitioners (Naji et al.. 1989) and may reflect either unease about asking such questions or concern about the quality of information they produce. Almost a third (31%) of students who said they would attempt to assess a patient’s risk status said they would ask whether the patient was a blood donor. Most students said they thought being a blood donor would indicate a person was an average to low risk of being infected by HIV (95.6%) or HBV (93.0%). This suggests they would use the information as a negative indicator of risk, rather than believing that donating blood is itself a risky behaviour. However, it ought to be matter for concern if such questions are being put to dental patients, as they may be
Nuttall
and Gilbert:
unaware of the subtlety underlying them and construe it as indicating that there is a risk associated with donating blood. The students also seemed to be concerned about the quality of blood transfusions in the UK; 22% said they would consider being a recent recipient of whole blood in the UK as an indication of high risk to HIV. Furthermore. over half (55%) of those who would question patients in order to establish their risk would ask if they had recently had a transfusion. Blood transfusions are a potential route for viral infection and accounted for 0.6% of cases reported to be HIV-antibody positive up to 1991 in Scotland; in comparison transmission by heterosexual intercourse accounted for 9.4% of cases (Common Services Agency, 1991). The students in this study therefore seem to be quite prepared to ask questions with relatively little predictive value but having the very real danger of causing considerable alarm and anxiety among some patients (those who have had blood transfusions). yet are not prepared to ask what are perhaps much more pertinent questions presumably because they might cause embarrassment. If dentists do intend to formulate their cross-infection strategies in conjunction with assessments of a patient’s risk (despite recommendations by authoritative bodies that they should not). they should be much more prepared to ask about behaviours which have a higher predictive value of risk. The students’ views on the relative risk of tourists from various countries can be compared with reported rates of AIDS infection throughout the world (Pindborg, 1992). German, Danish and Dutch tourists were regarded as average or lower risk for HIV infection by 99%. 91% and 76% of the students respectively: yet their reported rates of AIDS cases in 1990 (85. 127 and 94 cases per million) exceeds the reported rate of 60 cases per million in the UK. However. 38% of the students thought tourists from Japan would be a lower than average risk and the same view was held by 40% of the students about tourists from the former Soviet Union. These views would be borne out by their reported AIDS rates of 2.3 and 0.1 per million respectively. The 119 students who indicated that they would assess the risk status of patients using some sort of observable cues in order to step up their cross-infection precautions (14%) or in order to decide whether to ask questions which might reveal risk status (15%) were given a checklist of potential observable factors and asked which would make them think a patient may be a high risk. The finding that none of the items were identified as risk indicators by more than half of the students suggests that there may be a great deal of variability in opinion about which observable factors may aid identification of a high-risk individual. Classifying people as high or low risk by observation, without asking specific questions about behaviour. seems unlikely to be a particularly successful way of detecting a large proportion of undetected infected patients, although it is clear from this present study that some dental students think they are capable of doing so. as do some general dental practitioners (Kay et al., 1990).
Assessment
of cross-infection
risk by students
103
The significance of the finding that many final year dental students intend to base their future cross-infection strategies on assessments of their patients’ risk status depends on what is done with the information. It would be perhaps a rather different matter if, for example, an assessment of risk is undertaken to determine whether to wear two pairs of gloves rather than one, as against the information being used to decide whether to wear any gloves at all. The results suggest that almost all students, as a matter of routine, intend to wear some form of glove and use an autoclave for sterilizing hand instruments. However. there was less support for the routine use of surgical gowns, eye protection and surgical masks among the students who said they would assess the risk status of patients in order to step up cross-infection precautions when appropriate. This suggests that these might be the type of precautions which are used in addition to routine precautions by those who say they intend to use a twostage cross-infection strategy based on their perception of a patient’s risk.
CONCLUSION This study has found that final year dental students think they can identify high-risk patients by a variety of means. and would attempt to do so in order to step up their crossinfection control precautions. Those who would take personal histories seem prepared to ask about experiences which have relatively low predictive value for infection (e.g. blood transfusions). but some are reluctant to ask more pertinent questions, i.e. those concerning sexual activity. Those who would attempt to assess patients’ risk status by observation, without asking’intrusive questions’. seem to have differing views about what sort of factors would be useful in coming to an assessment. It is perhaps an evolutionary feature of human behaviour that people are natural assessors of risk and that actions will be tailored to fit an individual’s perception of the danger of any given situation. Nevertheless, there is perhaps a need when undertaking clinical work to override what may be a natural adaptive behaviour at other times. The danger in believing that the carrier status of patients can be reliably determined by questioning or observation. in order to decide when to take additional precautions. is that it may eventually lead to complacency in maintaining an adequate cross-infection control programme in routine clinical care.
Acknowledgements We would like to thank all the students who took the time to complete the questionnaire and the local contacts and Deans of the dental schools of Belfast. Birmingham, Bristol, Cardiff. Dundee. Edinburgh. Glasgow. Guys. Leeds. Liverpool, The London Hospital, Manchester, Newcastle, Sheffield, and University College, London. The study was supported by a grant from the Scottish
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Office Home and Health Department who do necessarily share the views expressed in this article.
not
References British Dental Association (1991) The Control of Crossinfection in Dentistry. Advice Sheet A12. London. British Dental Association. Centers for Disease Control. (1989) Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis B virus to health-care and public-safety workers. MMWR 381 No. S-6. Common Services Agency (1991) Scotfish Health SraWics 1991. Edinburgh. Information and Statistics Division of the Commons Services Agency for the Scottish Health Service. p. 27. Fitzpatrick R.. Boulton M.. Hart G. et al. (1989) High risk sexual behaviour and condom use in a sample of homosexual and bisexual men. Health Trends 3, 76-79. Gerbert B. (1987) AIDS and infection control in dental practice: dentists’ attitudes. knowledge and behaviour. J. Am. Dent. Assoc. 114, 311-314.
Forthcoming Original
Research
Morphology
of coupling
Kay E. J., Murray K. and Blinkhorn A. S. (1990) AIDS and immunodeficiency virus: a preliminary investigation into Edinburgh general dental practitioners’ views and behaviours. Health Educ. Res. 5, 321-325. Lindsay S. J. E. and New M. (1992) Implementing universal precautions against infection. Br. Dent. J. 172, 297. Naji S.. Russell I., Moore M. et al. (1989) HIV Infection and Scottish General Practice. Findings of a National Sample Survey. Report No. 2. Aberdeen. Health Services Research Unit. Nuttall N. M. and Gilbert A. D. (1993) Final year dental students’ views on cross-infection precautions. J. Dent 105-l 10. Pindborg J. J. (1992) Global aspects of the AIDS epidemic. Oral Surs. Oral Med. Oral Pathol. 73, 138-141. Pitts N. B. and Nuttall N. M. (1988) Precautions reported to be used against cross-infection and attitudes to the dental treatment of HIV-positive patients in routine clinical practice in Scotland. J. Dent. 16, 258-263. Scully C.. Porter S. R. and Epstein J. (1992) Compliance with infection control procedures in a dental hospital clinic. Br. Dent. J. 173, 20-23.
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